Okay I have been playing with this one in my head for a while, but other than the obvious difference of 16% versus 15 and 17, what are the main differences. Why should I choose one over the other?

 

just to complicate things further - putting brand and % aside - another difference is that some are 4 bolt design and others 6 bolt design.

What you will learn is that they are all good.

 

thread pitch is different on the m7 plus all the other stuff that peter lists on his site about his pulley's ...its a NiCER lookin' piece to if ur into that

 

Don't forget about these, they are excellent;
http://www.helix13.com/html/products...ew.php?p=6&h=m

Once it's installed your not going to be able to see very much of it so looks really don't matter if the seller is advertising a BLING factor.

 

Other than 'more is better', why do you prefer 6? Have any failures/weakness been identified with the four screw design?

 

The helix / RDR - Good stuff . BLING - It would be better if pulleys were black w/ no branding - making it that much hard for a dealer to identify. Some dealers can be a real pain in the ..............

 

I went through the same questions when I was doing my pulley. I have a 6 bolt RDR (helix) and no problems whatsoever. The reality is that there are hundreds / thousands of 4 bolts out there running just fine. If installed correctly either should serve you well.

 

The good news is that they are both GREAT! You will not regret either one and wish you would have bought the other one afterwards. Randy webb uses both m7 and alta at his pulley parties. I decided on the m7 because it's 1% more, which suppose to be faster but still safe enough. And m7 has small holes to prevent overheating which theoriticly should work but not really proven in any data.

 

I have the m7 pulley on my Dark Silver car and have had no problems with it at all. It really woke up when I added the Dinan air box. BUT, the bolts that come with it have started to rust and look like crap.
I'm thinking of using the Alta 17% on my Jet Black car.

 

Webb Motorsports recently installed an M7 pulley on my Mini, and I have been really happy with its performance -- there's no question it helps to put more power to the ground -- and it really makes the car feel "alive" like a little beast. Personally I also really like the trick look of the M7 piece (and you can still see the side of it in the engine bay).

I have heard the Alta 15% serves a similar purpose in terms of performance, so you really can't go wrong either way...

 

Hmm I guess if they could come in black for a steath install it would make it much better . Not sure why everyone chooses silver.

so the M7 is a simular design with the alta, IE in terms of 4 bolts versus 6 then eh?

 

Check out this page for a comparison (including photos), and this page for an explanation of why you probably should not go more than a 15-16% reduction. Randy, Brian, and Bridget would also appreciate your support -- WMS is a true advocate for the Mini community!

 

Thanks so much. Ohh I plan on supporting them as soon as the WMS exhaust comes out. I have talked with randy numerous times. They seem like a great bunch of people. I bet they are really fun to work for.

 

Because black aluminum is very rare and expensive . We all have our favorite vendor/brand, pick yours and pulley up. As another person said it really changes the character of the car. I descibe it as giving the car much more road presence. And while you have your wallet out - mod the air cleaner and exhaust. Cheaply, change the stock filter over to an ITG Foam and do the one-ball exhaust. Both just compliment the pulley.

for entertainment value add a boost guage.

I started out "just doing the pulley" (like so many here at NAM) and you will see below what has happened. The mini is an addictive little bugger because every pony you add you can feel.

 

Hi everyone

The reason for us using the "Black Bolts" are simple, they are stronger
then the stainless steel with higher tensile strength, and the chance of
them shearing of is very small. I will have a box of SS bolts available to
anyone who want's it with our pulley, just call me it's free of charge....

peter
Team M7
562-608-8123

 

what size of bolt is it? 1/4"? I could really see the need for 4 engineering whise let alone 6 if thats the case. I think the tensile strength on a bolt like that is what 50,000-psi. Quite an overdesign to bring peace of mind for people .

And I was refering to the color of the pulley itself

 

I recently got "Supercharged!" by Corky Bell. It goes over all the stuff on pully selection. The reference doesn't account for belt tension, radius of curvature, belt wrap etc. From an engineering standpoint, it makes more sense to up the crank pully diameter as much as it can go, and decrease the SC pully the min needed to get the RPM ratio factor that you want....

But what is this factor? I you're a track rat, living at high RPM, the SC efficiency and belt issues at high RPM come into play and you'd want to limit the SC pully reduction. If you're a street driver that rarely goes over 5k RPM, then the 19% will give you more bump at the bottom end.

There is no right answer to these questions. There is best match to desired function though. And If you want to have a better idea on how to figure all this stuff out, Corky's book is an excellent place to learn how SC motors work, the pros and cons of different approaches and the trade offs involved.

Matt

 

I drive on the street and always go above 5k. It's fun to hear the pretty pur and growl of the engine. Heck I bought the car to have fun with. It's my "fun car". I have a '90 mustang with 348hp for fun stuff. But well you know straight line driving is boring .

The mini I am trying to get power to overcome semi trucks and to have the
power to overcome items that I feel are important while driving. I highly intend on taking lots of driving courses with this car and learning the correct "how to drive".

The point of this pulley would be to gain that like extra power to overcome such obstacles. I know some of you would disagree this my reasoning however, I have been in situations before where split second reaction times are highly important, and having the power to overcome them is quite a necessity!

Drive on the 405 in LA and you would understand. Although I think the 405 is safer than the yahoos on the 5

 

Are you going to send me the stainless ones for free Peter?

 

It's a pretty fascinating book, isn't it? The only downside is it doesn't really address OEM supercharged applications like ours, but then again, all of us on NAM are writing those chapters.

 

Yes I will

Call me..

peter
Team M7
562-608-8123

 

You are absolutely correct. The benefit of these chapters on NAM is that they are, by definition, written of collective insight .

 

Hopefully the pages are copyrighted

 

But it's not a big deal. I've also got "Forced Induction Performance Tuning" by A. Graham Bell that's next on the reading list. But Corky's book is the first one I read that really covers all aspects of SC systems. Grahams book takes a more open minded look at water injection, and comes to close to the same conclusion. Don't waste time unless the specific class run doesn't allow ICs.... But I've just skimmed the Graham book. It is heavier.....


Matt

 

For what its worth, I have an M7 16% pulley, and a HAI, and I push 17lbs peak. I really loved the finish of the M7...the overall quality of the piece sold me.